Extruded modular panels with upstanding seam flanges made of polycarbonate and other resins are widely used in the design of various architectural structures because they are a strong, lightweight alternative to traditional materials, like glass, which they often replace. For example, such modular glazing panels joined along abutting upstanding seam flanges that extend along their edges can be used either alone or with a supporting framework of, e.g., purlins or rafters, to form overhead or roofing structures. The ability of such panels to transmit light has made them particularly useful where it is desired to allow sunlight to pass into a structure such as to illuminate the interior region of a building. An additional advantage of these panels is that they have good energy conservation and sound insulation characteristics. Indeed, it has been found that when such glazing panels are paired one over the other into a unit with an enclosed airspace between the panel pair, improved energy conservation and sound insulation properties can be achieved. Paired extruded modular panels also have greater structural strength making them useful in applications where single panel units could not be used or would require additional supporting elements.
Each modular upstanding seam flange glazing panel is typically up to 40 feet in length, 2-4 feet wide and flexible. It therefore requires substantial skill and is time-consuming to assemble and install panel pairs on-site. The challenge to assembling and installing the panel pairs faced by such skilled workers can be appreciated, for example, by examining FIG. 1 which illustrates a current representative panel pair assembly system. More particularly, FIG. 1 shows a purlin 1 and one of a series of myriad metal retaining clips 2 affixed along the purlin. The retaining clips include horizontal flanges 3. Once the series of spaced retaining clips are in place on the purlin (or other supporting member), polycarbonate (or other resin) bottom modular panels 4A and 4B are manipulated into position and slid horizontally under the flanges of the retaining clips. Then, an elongated resilient batten joint connector 5 with a downwardly facing elongated bottom cavity 6A is forced down over the upstanding seam flanges 7A and 7B of modular panels 4A and 4B to lock them onto the retaining clips by way of sawteeth in the bottom cavity that mate with sawteeth on the flanges of the bottom panels. Finally, top modular panels 8A and 8B are manipulated into position with their seam flanges 9A and 9B aligned with the upwardly facing elongated top cavity 6B in the batten joining connector and pressed into place with the sawteeth of flanges 9A and 9B of modular panels 8A and 8B held in place by corresponding sawteeth within cavity 6B.
While there are many typically inferior variations on the paired modular panel unit system of FIG. 1, it is indicative of the relative complexity of assembling and installing sloped glazing, skylights, roofs, walls and other architectural structures having paired modular panel units on-site. The system of FIG. 1 also illustrates the conventional metal (retaining clip) to polycarbonate skin (flange of panel) contact employed in current modular upstanding seam panel retention systems. Because those skilled in this art have been wed to fixing the panels in place through such direct engagement of an unforgiving hard or high ultimate tensile strength metal retention clip against the resilient low ultimate tensile strength skin of the polycarbonate modular panel, it has been necessary to take extra steps to ensure that load specifications are met. For example, skin weight of the panel flanges is greater than it otherwise would need to be in order to prevent cracking of the polycarbonate skin of the flanges under load. This excess weight results in unnecessary material usage/cost and less than optimal light transmission. Also, large numbers of closely spaced retention clips are often required to meet wind load and other load specifications by spreading out the load across more clips also to prevent cracking of the polycarbonate skin of the flanges under load.
There is therefore a great need for a system that makes it easier and less time-consuming to assemble and install or erect paired modular panel units. If such a system also provided a completed architectural glazing structure comprised of modular upstanding seam flange panels which is safe, secure, surprisingly strong and able to withstand substantially increased wind loads, a particularly unexpected and useful contribution to the art would be at hand. If such a system further eliminated the inherent limitations of conventional metal-to-polycarbonate engagement, required fewer retention clips, and made it possible to reduce panel flange skin thickness an extremely important and unexpected advance in the art would be in the offing.
The present invention provides such a system for readily assembling together pairs of such modular glazing panels either on-site (but in convenient ground level work areas) or off-site and then readily installing the pre-assembled modular panel units on-site to erect the sloped glazing, skylights, roofs, walls, and other architectural structures. This new system is particularly elegant in that it armors the standing seams of the modular panels to thereby provide a unique new metal-to-metal retention that withstands increased wind and snow loads while making it possible to reduce the weight of the polycarbonate skin of the flanges and optionally to use bottom or inner panels with lighter skins across the entire panel. It is also surprisingly economical in terms of materials (e.g., reduced number of retention clips and thinner polycarbonate skins) and in terms of construction costs since it can be erected quickly and generally without special skills, and produces architectural structures that can accommodate wider spans, are surprisingly effective in limiting air, water and sound infiltration, and have outstanding energy conservation characteristics. Indeed, the present system makes it possible to readily insert infill into the airspace between the panels off-site (or on-site) in the form of translucent insulation (e.g., glass fiber), or to add metal screening for improving the fire resistance of the panel unit and for resisting severe localized impacts on the outer panel. It is extremely difficult and expensive to add infill to prior art panel units which must be assembled on-site.
Finally, it is important to accommodate horizontal expansion and contraction of the modular panels. While prior systems for assembling and installing panel pairs have a limited ability to accommodate such expansion and contraction, the use of the interlocking male and female locking engagement members of the present invention accommodates such horizontal expansion and contraction far better than any earlier design and in a way not remotely contemplated by those skilled in this art.